The finishing of the track of a bearing race by grinding presents some difficult problems. This is particularly true in grinding the surfaces of the track of a roller bearing. Normally, the end of the race is located against the flat radial surface of a drive platen and the abrasive wheel is advanced axially to a point which is a fixed distance away from the platen. If the end-to-end dimension of all workpieces were the same, this would result in a track width and a lip thickness which are exactly the same from one workpiece to another. Unfortunately, the end surfaces of a finished bearing race are not critical either in their location or their finish, so that the end-to-end distance carries over a wide range of dimensions from one workpiece to another. When the conventional grinding system described above is used for processing tracks, therefore, the width varies from one workpiece to another. Since the width of the track is a critical dimension in the construction and operation of the bearing, this is unacceptable. One alternative that is available is to grind the end surfaces to a selected distance within a narrow range of tolerances. This, however, is not only expensive, but represents a waste of processing time, labor, and equipment, since perfectly acceptable bearings can be constructed when the end distances varies over fairly wide range of tolerances. Another alternative is to finish the radial surface of one lip and then reverse the workpiece and grind the radial surface of the other lip by inserting a gage that measures the distance between the lips continuously and allows the advance of the grinding operation on the second lip to take place only until the gage indicates that the proper width has been arrived at. Not only is this difficult to do, because of the presence of the gage in the workpiece while the grinding is progressing, but it requires expensive, delicate instrumentation. Furthermore, it produces lips that are different in their thickness, even though the width of the track is the selected one within a narrow range of tolerances. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a grinding machine for producing perfectly centered tracks and grooves on bearing races.
Another object of the present invention is the provision of a grinding machine for producing roller tracks in roller bearing races in which the track has a width which is accurate to a high degree of tolerances, despite variations in the end-to-end dimension of the workpieces.
A further object of the present invention is the provision of a grinding machine for producing a track on a bearing race that is perfectly centered in the end-to-end dimension.
It is another object of the instant invention to provide a method of grinding perfectly centered tracks on a bearing race to a predetermined width.
A still further object of the invention is the provision of a method of grinding a bearing race track within a predetermined tolerance of width and the lip thickness.
It is a further object of the invention to provide a method of grinding tracks on bearing races in such a way that they are accurately formed and located, despite wide variations in the end-to-end dimensions of the rough workpieces.
It is a still further object of the present invention to provide a grinding machine for forming in bearing races grooves and tracks of good quality and location, which grinding machine is simple in constructions, inexpensive to manufacture, and which is capable of a long life of useful service with a minimum of maintenance.
Another object of the invention is the provision of a method of grinding bearing race grooves which are accurately formed without the necessity of maintaining small tolerances on the end-to-end dimension in previous production steps.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.